New tight junction protein 2 variant causing progressive familial intrahepatic cholestasis type 4 in adults: A case report
Chunshan Wei, Naja Becher, J Friis, Peter Ott, Ida Vogel, Henning Grønbæk
Abstract
BACKGROUND: gene in adults with very variable expression of PFIC4. CASE SUMMARY: The index patient presented at 19 years old with liver cirrhosis and variceal bleeding and was treated with endoscopic banding and beta-blockers. In 2018, he developed primary liver cancer that was treated with radiofrequency ablation followed by liver transplantation in 2019. Genetic testing revealed a novel homozygous TJP2 variant causing PFIC4 (TJP2([NM_004817.3]:c.[3334C>T]; [3334C>T])). The consanguineous family consists of the father and mother (both heterozygous) and their 12 children, of which five carry the variant in a homozygous state; however, these five siblings have highly variable expression of PFIC4. Two homozygous brothers had cirrhosis and portal hypertension at diagnosis at the ages of 19 and 36. Two other homozygous brothers, age 23 and 19, and the homozygous sister, age 21, have elevated liver enzymes but presently no cirrhosis, which may suggest an age-dependent penetrance. In addition, five sisters had severe and mild intrahepatic cholestasis of pregnancy and carry the TJP2 variant in a homozygous and heterozygous state, respectively. CONCLUSION: This novel TJP2 variant is associated with PFIC4 causing severe liver disease with cirrhosis and primary liver cancer in adolescents/adults.